Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. A primary challenge is to make effective use of the limited and dynamic network capacity. While one dominant application for LLNs, initially, is to support Automated Meter Reading (AMR), such networks may also be used to support multiple applications simultaneously, such as distributed sensing, actuation, etc. Accordingly, the LLNs must sometimes be configured to provide a multi-service network infrastructure. Other example applications include Distribution Automation (DA), plug-is in electric vehicles, etc. Such applications typically involve different traffic characteristics and requirements (e.g., point-to-point vs. multipoint-to-point, different latency bounds, etc.).
While a Network Management System (NMS) that is responsible for the LLN is primarily a control-plane function, management of the network itself can be considered to utilize a number of different applications simultaneously. By contrast with a “classic” IP network, such functions can consume a very significant portion of the constrained resources of an LLN. Some example functions include firmware updates, security updates, configuration changes, on-demand control and query, etc. Most of these functions involve interactions where the NMS sends out a single request, nodes process the request, and generate a response.
In large-scale LLNs, if nodes naively respond to a request, the response traffic can easily overwhelm the network, in what is called a “response-implosion” problem. That is, the generation of such a large amount of traffic in LLNs is particularly problematic, with generally very limited network/node resources and the large number of nodes in the typical LLN deployment. Existing and widely deployed approaches to Quality of Service (QoS) and Call Admission Control (CAC) typically used in “classic” IP networks, however, are ill-suited for LLNs. Heavy signaling can easily overwhelm the limited network capacity, while strict resource reservation mechanisms cannot operate effectively when there are not enough resources to allocate (limited memory).